This invention relates generally to novel 5-substituted-indeno[1,2-c]pyrazol-4-ones which are useful as cyclin dependent kinase (cdk) inhibitors, pharmaceutical compositions comprising the same, methods for using the same for treating proliferative diseases, and intermediates and processes for making the same.
One of the most important and fundamental processes in biology is the division of cells mediated by the cell cycle. This process ensures the controlled production of subsequent generations of cells with defined biological function. It is a highly regulated phenomenon and responds to a diverse set of cellular signals both within the cell and from external sources. A complex network of tumor promoting and suppressing gene products are key components of this cellular signaling process. Over expression of the tumor promoting components or the subsequent loss of the tumor suppressing products will lead to unregulated cellular proliferation and the generation of tumors (Pardee, Science 246:603-608, 1989).
Cyclin dependent kinases (cdks) play a key role in regulating the cell cycle machinery. These complexes consist of two components: a catalytic subunit (the kinase) and a regulatory subunit (the cyclin). To date, six kinase subunits (cdk 1-7) have been identified along with several regulatory subunits (cyclins A-H). Each kinase associates with a specific regulatory partner and together make up the active catalytic moiety. Each transition of the cell cycle is regulated by a particular cdk complex: G1/S by cdk2/cyclin E, cdk4/cyclin D1 and cdk6/cyclinD/2; S/G2 by cdk2/cyclin A and cdk1/cyclin A; G2/M by cdk1/B. The coordinated activity of these kinases guides the individual cells through the replication process and ensures the vitality of each subsequent generation (Sherr, Cell 73:1059-1065, 1993; Draetta, Trends Biochem. Sci. 15:378-382, 1990)
An increasing body of evidence has shown a link between tumor development and cdk related malfunctions. Over expression of the cyclin regulatory proteins and subsequent kinase hyperactivity have been linked to several types of cancers (Jiang, Proc. Natl. Acad. Sci. USA 90:9026-9030, 1993; Wang, Nature 343:555-557, 1990). More recently, endogenous, highly specific protein inhibitors of cdks were found to have a major affect on cellular proliferation (Kamb et al, Science 264:436-440, 1994; Beach, Nature 336:701-704, 1993). These inhibitors include p16INK4 (an inhibitor of cdk4/D1), p21CIP1 (a general cdk inhibitor), and p27KIP1 (a specific cdk2/E inhibitor). A recent crystal structure of p27 bound to cdk2/A revealed how these proteins effectively inhibit the kinase activity through multiple interactions with the cdk complex (Pavletich, Nature 382:325-331, 1996). These proteins help to regulate the cell cycle through specific interactions with their corresponding cdk complexes. Cells deficient in these inhibitors are prone to unregulated growth and tumor formation.
This body of evidence has led to an intense search for small molecule inhibitors of the cdk family as an approach to cancer chemotherapy.
A series of indeno[1,2-c]pyrazoles having anticancer activity are described in JP 60130521 and JP 62099361 with the following generic structure: 
A series of indeno[1,2-c]pyrazoles having herbicidal activity are described in GB 2223946 with the following generic structure: 
A series of 1-(6xe2x80x2-substituted-4xe2x80x2-methylquinol-2xe2x80x2-yl)-3-methylindeno[1,2-c]pyrazoles having CNS activity are described by Quraishi, Farmaco 44:753-8, 1989 with the following generic structure: 
There is a continuing unmet need for cdk inhibitors with which to treat proliferative diseases.
The present invention describes a novel class of indeno[1,2-c]pyrazol-4-ones or pharmaceutically acceptable salt forms thereof that are potent inhibitors of the class of enzymes known as cyclin dependent kinases, which relate to the catalytic subunits cdk 1-7 and their regulatory subunits know as cyclins A-H.
The present invention is also directed to a novel method of treating cancer or other proliferative diseases by administering a therapeutically effective amount of one of these compounds or a pharmaceutically acceptable salt form thereof.
A novel method of treating cancer or other proliferative diseases, which comprises administering a therapeutically effective combination of one of the compounds of the present invention and one or more other known anti-cancer or anti-proliferative agents is also described herein.
The present invention also describes compounds of formula (I): 
wherein R1, R2 and X are defined below or pharmaceutically acceptable salts thereof as cyclin dependent kinase inhibitors.
The invention pertains to novel cyclin dependent kinase inhibitors (cdks) and specifically, but not exclusively, as inhibitors of cdk/cyclin complexes. The inhibitors of this invention are indeno[1,2-c]pyrazol-4-one analogs. Certain analogs were selective for their activity against cdks and their cyclin bound complexes and were less active against other known serine/threonine kinases such as Protein Kinase A (PKA) and Protein Kinase C (PKC). In addition, these inhibitors were less active against tyrosine kinases such as c-Ab1.
As described herein, the inhibitors of this invention are capable of inhibiting the cell-cycle machinery and consequently would be useful in modulating cell-cycle progression, which would ultimately control cell growth and differentiation. Such compounds would be useful for treating subjects having disorders associated with excessive cell proliferation, such as the treatment of cancer, psoriasis, immunological disorders involving unwanted leukocyte proliferation, in the treatment of restinosis and other smooth muscle cell disorders, and the like.
The present invention, in a first embodiment, describes a novel compound of formula (I): 
or a stereoisomer or pharmaceutically acceptable salt form thereof, wherein:
X is selected from the group: O, S, and NR;
R is selected from the group: H, C1-4 alkyl, and NR5R5a;
R1 is selected from the group: H, C1-10 alkyl substituted with 0-3 Rc, C2-10 alkenyl substituted with 0-3 Rc, C2-10 alkynyl substituted with 0-3 Rc, C1-10 alkoxy, xe2x80x94NHR4, C3-10 carbocycle substituted with 0-5 Ra, and 3-10 membered heterocycle containing from 1-4 heteroatoms selected from O, N, and S and substituted with 0-5 Rb;
R2 is selected from the group: H, C1-10 alkyl substituted with 0-3 Rc, C2-10 alkenyl substituted with 0-3 Rc, C2-10 alkynyl substituted with 0-3 Rc, xe2x80x94(CF2)mCF3, C3-10 carbocycle substituted with 0-5 Ra, and 3-10 membered heterocycle containing from 1-4 heteroatoms selected from O, N, and S and substituted with 0-5 Rb;
R3 is selected from the group: H, halo, xe2x80x94CN, NO2, C1-4 haloalkyl, NR5R5a, NR5NR5R5a, NR5C(O)OR5, NR5C(O)R5, xe2x95x90O, OR5, COR5, CO2R5, CONR5R5a, NHC(O)NR5R5a, NHC(S)NR5R5a, SO2NR5R5a, SO2R5b, C1-4 alkyl, phenyl, benzyl, C1-4 alkyl substituted with 1-3 Rc, C5-10 alkyl substituted with C2-10 alkenyl optionally substituted with 0-3 R6, C2-10 alkynyl substituted with 0-3 R6, xe2x80x94(CF2)mCF3, C3-10 carbocycle substituted with 0-5 R6, and 5-10 membered heterocycle containing from 1-4 heteroatoms selected from O, N, and S, substituted with 0-3 R6; and
provided that if R3 is phenyl, it is substituted with 1-5 Ra;
R4 is independently at each occurrence selected from the group: H, xe2x80x94CN, C1-4 alkyl, C1-4 haloalkyl, NR3R3a, NR3C(O)OR3, NR3C(O)R3, OR3, COR3, CO2R3, CONR3R3a, NHC(O)NR3R3a, NHC(S)NR3R3a, SO2NR3R3a, SO2R3b, C3-10 carbocycle substituted with 0-5 Ra, and 5-10 membered heterocycle containing from 1-4 heteroatoms selected from O, N, and S, substituted with 0-3 R3;
provided that at least one R3 is present and that this R3 is selected from the group: C1-4 alkyl substituted with 1-3 R6, C5-10 alkyl substituted with C2-10 alkenyl optionally substituted with 0-3 R6, C2-10 alkynyl substituted with 0-3 R6, xe2x80x94(CF2)mCF3, C3-10 carbocycle substituted with 0-5 R6, and 5-10 membered heterocycle containing from 1-4 heteroatoms selected from O, N, and S, substituted with 0-3 R6;
Ra is independently at each occurrence selected from the group: halo, xe2x80x94CN, N3, NO2, C1-4 alkyl, C1-4 haloalkyl, NR3R3a, xe2x95x90O, OR3, COR3, CO2R3, CONR3R3a, NHC(O)NR3R3a, NHC(S)NR3R3a, NR3C(O)OR3, NR3C(O)R3, SO2NR3R3a, SO2R3b, and 5-10 membered heterocycle containing from 1-4 heteroatoms selected from O, N, and S;
alternatively, when two R2, are present on adjacent carbon atoms they combine to form xe2x80x94OCH2Oxe2x80x94 or xe2x80x94OCH2CH2Oxe2x80x94;
Rb is independently at each occurrence selected from the group: halo, xe2x80x94CN, NO2, C1-4 alkyl, C1-4 haloalkyl, NR3R3a, NR3C(O)OR3, NR3C(O)R3, OR3, COR3, CO2R3, CONR3R3a, NHC(O)NR3R3a, NHC(S)NR3R3a, SO2NR3R3a, and SO2R3b;
Rc is independently at each occurrence selected from the group: halo, xe2x80x94CN, NO2, C1-4 alkyl, C1-4 haloalkyl, NR3R3a, NR5NR5R5a, NR3C(O)OR3, NR3C(O)R3, xe2x95x90O, OR3, COR3, CO2R3, CONR3R3a, NHC(O)NR3R3a, NHC(S)NR3R3a, SO2NR3R3a, SO2R3b, C3-10 carbocycle substituted with 0-5 Ra, and 5-10 membered heterocycle containing from 1-4 heteroatoms selected from O, N, and S, substituted with 0-3 R3;
R3a is selected from the group: H, C1-4 alkyl, phenyl, and benzyl;
alternatively, R3 and R3a, together with the nitrogen atom to which they are attached, form a heterocycle having 4-8 atoms in the ring containing an additional 0-1 N, S, or O atom and substituted with 0-3 R3c;
R3b is selected from the group: H, C1-4 alkyl, phenyl, and benzyl;
R3c is independently at each occurrence selected from the group: halo, xe2x80x94CN, N3, NO2, C1-4 alkyl, C1-4 haloalkyl, NR3R3b, xe2x95x90O, OR3, COR3, CO2R3, CONR3R3b, NHC(O)NR3R3b, NHC(S)NR3R3b, NR3C(O)OR3, NR3C(O)R3, SO2NR3R3b, SO2R3b, and 5-10 membered heterocycle containing from 1-4 heteroatoms selected from O, N, and S;
R5 is independently selected from the group: H, C1-4 alkyl, phenyl and benzyl;
R5a is independently selected from the group: H, C1-4 alkyl, phenyl and benzyl;
R5b is independently selected from the group: H, C1-4 alkyl, phenyl and benzyl;
R6 is independently at each occurrence selected from the group: halo, xe2x80x94CN, NO2, C1-4 alkyl, C1-4 haloalkyl, NR5R5, NR5NR5R5a, NR5C(O)OR5, NR5C(O)R5, xe2x95x90O, OR5, COR5, CO2R5, CONR5R5a, NHC(O)NR5R5a, NHC(S)NR5R5a, SO2NR5R5a, SO2R5b, C3-10 carbocycle substituted with 0-5 R5, and 5-10 membered heterocycle containing from 1-4 heteroatoms selected from O, N, and S, substituted with 0-3 R5; and
m is selected from 0, 1, 2, and 3.
In another embodiment of the present invention, the compounds of formula (I) are selected from:
3-(4-methoxyphenyl)-5-(2-benzoylhydrazinecarboxamido)indeno[1,2-c]pyrazol-4-one;
3-(4-methoxyphenyl)-5-(2-isonicotinoylhydrazinecarboxamido)indeno[1,2-c]pyrazol-4-one;
3-(4-methoxyphenyl)-5-(2-nictinoylhydrazinecarboxamido)indeno[1,2-c]pyrazol-4-one;
3-(4-methoxyphenyl)-5-(2-(3,4-dihydroxybenzoyl)hydrazinecarboxamido)indeno[1,2-c]pyrazol-4-one;
3-(4-methoxyphenyl)-5(2-(4-hydroxybenzoyl)hydrazinecarboxamido)indeno[1,2-c]pyrazol-4-one;
3-(4-methoxyphenyl)-5-(2-(3-aminobenzoyl) hydrazinecarboxamido)indeno[1,2-c]pyrazol-4-one;
3-(4-methoxyphenyl)-5-(2-(4-aminobenzoyl)hydrazinecarboxamido)indeno[1,2-c]pyrazol-4-one;
3-(4-methoxyphenyl)-5-(2-(2-aminobenzoyl)hydrazinecarboxamido)indeno[1,2-c]pyrazol-4-one;
3-(4-methoxyphenyl)-5-(2-(4-N,N-dimethylaminobenzoyl)hydrazinecarboxamido)indeno[1,2-c]pyrazol-4-one;
3-(4-methoxyphenyl)-5-(2-phenethylacetylhydrazinecarboxamido)indeno[1,2-c]pyrazol-4-one;
3-(4-methoxyphenyl)-5-(2-(2-hydroxybenzoyl)hydrazinecarboxamido)indeno[1,2-c]pyrazol-4-one; and
3-(4-methoxyphenyl)-5-(2-methoxycarbonylhydrazinecarboxamido)indeno[1,2-c]pyrazol-4-one;
1-[3-(4-methoxy-phenyl)-4-oxo-2,4-dihydro-indeno[1,2-c]pyrazol-5-yl]-3-morpholin-4-yl-urea;
[3-(4-methoxy-phenyl)-4-oxo-2,4-dihydro-indeno[1,2-c]pyrazol-5-yl]-urea;
1-(2-amino-cyclohexyl)-3-[3-(4-methoxy-phenyl)-4-oxo-2,4-dihydro-indeno[1,2-c]pyrazol-5-yl]-urea;
2-(4-aminomethyl-piperidin-1-yl)-N-[3-(4-methoxy-phenyl)-4-oxo-2,4-dihydro-indeno[1,2-c]pyrazol-5-yl]-acetamide;
1-[3-(4-methoxy-phenyl)-4-oxo-2,4-dihydro-indeno[1,2-c]pyrazol-5-yl]-3-morpholin-4-yl-urea.
or pharmaceutically acceptable salt form thereof.
Another embodiment of the present invention is a pharmaceutical composition comprising: a pharmaceutically acceptable carrier and a therapeutically effective amount of a compound of formula (I).
Another embodiment of the present invention is a method of treating cancer and proliferative diseases comprising: administering to a host in need of such treatment a therapeutically effective amount of a compound of formula (I), or a pharmaceutically effective salt form thereof.
As used herein, the following terms and expressions have the indicated meanings. The compounds of the present invention may contain an asymmetrically substituted carbon atom, and may be isolated in optically active or racemic forms. It is well known in the art how to prepare optically active forms, such as by resolution of racemic forms or by synthesis from optically active starting materials. All chiral, diastereomeric, racemic forms and all geometric isomeric forms of a structure are intended, unless the specific stereochemistry or isomer form is specifically indicated.
The term xe2x80x9calkylxe2x80x9d is intended to include both branched and straight-chain saturated aliphatic hydrocarbon groups having the specified number of carbon atoms. Examples of alkyl include, but are not limited to, methyl, ethyl, n-propyl, i-propyl, n-butyl, s-butyl, t-butyl, n-pentyl, and s-pentyl. In addition, the term is intended to include both unsubstituted and substituted alkyl groups, the latter referring to alkyl moieties having one or more hydrogen substituents replaced by, but not limited to halogen, hydroxyl, carbonyl, alkoxy, ester, ether, cyano, phosphoryl, amino, imino, amido, sulfhydryl, alkythio, thioester, sulfonyl, nitro, heterocyclo, aryl or heteroaryl. It will also be understood by those skilled in the art that the substituted moieties themselves can be substituted as well when appropriate.
The terms xe2x80x9chaloxe2x80x9d or xe2x80x9chalogenxe2x80x9d as used herein refer to fluoro, chloro, bromo and iodo. The term xe2x80x9carylxe2x80x9d is intended to mean an aromatic moiety containing the specified number of carbon atoms, such as, but not limited to phenyl, indanyl or naphthyl. The terms xe2x80x9ccycloalkylxe2x80x9d and xe2x80x9cbicycloalkylxe2x80x9d are intended to mean any stable ring system, which may be saturated or partially unsaturated. Examples of such include, but are not limited to, cyclopropyl, cyclopentyl, cyclohexyl, norbornyl, bicyclo[2.2.2]nonane, adamantly, or tetrahydronaphthyl (tetralin).
As used herein, xe2x80x9ccarbocyclexe2x80x9d or xe2x80x9ccarbocyclic residuexe2x80x9d is intended to mean any stable 3- to 7-membered monocyclic or bicyclic or 7- to 13-membered bicyclic or tricyclic, any of which may be saturated, partially unsaturated, or aromatic. Examples of such carbocycles include, but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, adamantyl, cyclooctyl,; [3.3.0]bicyclooctane, [4.3.0]bicyclononane, [4.4.0]bicyclodecane (decalin), [2.2.2]bicyclooctane, fluorenyl, phenyl, naphthyl, indanyl, adamantyl, or tetrahydronaphthyl (tetralin).
As used herein, the term xe2x80x9cheterocyclexe2x80x9d or xe2x80x9cheterocyclic systemxe2x80x9d is intended to mean a stable 5- to 7-membered monocyclic or bicyclic or 7- to 10-membered bicyclic heterocyclic ring which is saturated partially unsaturated or unsaturated (aromatic), and which consists of carbon atoms and from 1 to 4 heteroatoms independently selected from the group consisting of N, O and S and including any bicyclic group in which any of the above-defined heterocyclic rings is fused to a benzene ring. The nitrogen and sulfur heteroatoms may optionally be oxidized. The heterocyclic ring may be attached to its pendant group at any heteroatom or carbon atom which results in a stable structure. The heterocyclic rings described herein may be substituted on carbon or on a nitrogen atom if the resulting compound is stable. If specifically noted, a nitrogen in the heterocycle may optionally be quaternized. It is preferred that when the total number of S and O atoms in the heterocycle exceeds 1, then these heteroatoms are not adjacent to one another. It is preferred that the total number of S and O atoms in the heterocycle is not more than 1. As used herein, the term xe2x80x9caromatic heterocyclic systemxe2x80x9d is intended to mean a stable 5- to 7-membered monocyclic or bicyclic or 7- to 10-membered bicyclic heterocyclic aromatic ring which consists of carbon atoms and from 1 to 4 heterotams independently selected from the group consisting of N, O and S. It is preferred that the total number of S and O atoms in the aromatic heterocycle is not more than 1.
Examples of heterocycles include, but are not limited to, 1H-indazole, 2-pyrrolidonyl, 2H,6H-1,5,2-dithiazinyl, 2H-pyrrolyl, 3H-indolyl, 4-piperidonyl, 4aH-carbazole, 4H-quinolizinyl, 6H-1,2,5-thiadiazinyl, acridinyl, azocinyl, benzimidazolyl, benzofuranyl, benzothiofuranyl, benzothiophenyl, benzoxazolyl, benzthiazolyl, benztriazolyl, benztetrazolyl, benzisoxazolyl, benzisothiazolyl, benzimidazalonyl, carbazolyl, 4aH-carbazolyl, b-carbolinyl, chromanyl, chromenyl, cinnolinyl, decahydroquinolinyl, 2H,6H-1,5,2-dithiazinyl, dihydrofuro[2,3-b]tetrahydrofuran, furanyl, furazanyl, imidazolidinyl, imidazolinyl, imidazolyl, 1H-indazolyl, indolenyl, indolinyl, indolizinyl, indolyl, isobenzofuranyl, isochromanyl, isoindazolyl, isoindolinyl, isoindolyl, isoquinolinyl, isothiazolyl, isoxazolyl, morpholinyl, naphthyridinyl, octahydroisoquinolinyl, oxadiazolyl, 1,2,3-oxadiazolyl, 1,2,4-oxadiazolyl, 1,2,5-oxadiazolyl, 1,3,4-oxadiazolyl, oxazolidinyl., oxazolyl, oxazolidinylperimidinyl, phenanthridinyl, phenanthrolinyl, phenarsazinyl, phenazinyl, phenothiazinyl, phenoxathiinyl, phenoxazinyl, phthalazinyl, piperazinyl, piperidinyl, pteridinyl, piperidonyl, 4-piperidonyl, pteridinyl, purinyl, pyranyl, pyrazinyl, pyrazolidinyl, pyrazolinyl, pyrazolyl, pyridazinyl, pyridooxazole, pyridoimidazole, pyridothiazole, pyridinyl, pyridyl, pyrimidinyl, pyrrolidinyl, pyrrolinyl, pyrrolyl, quinazolinyl, quinolinyl, 4H-quinolizinyl, quinoxalinyl, quinuclidinyl, carbolinyl, tetrahydrofuranyl, tetrahydroisoquinolinyl, tetrahydroquinolinyl, 6H-1,2,5-thiadiazinyl, 1,2,3-thiadiazolyl, 1,2,4-thiadiazolyl, 1,2,5-thiadiazolyl, 1,3,4-thiadiazolyl, thianthrenyl, thiazolyl, thienyl, thienothiazolyl, thienooxazolyl, thienoimidazolyl, thiophenyl, triazinyl, 1,2,3-triazolyl, 1,2,4-triazolyl, 1,2,5-triazolyl, 1,3,4-triazolyl, xanthenyl. Preferred heterocycles include, but are not limited to, pyridinyl, furanyl, thienyl, pyrrolyl, pyrazolyl, imidazolyl, indolyl, benzimidazolyl, 1H-indazolyl, oxazolidinyl, benzotriazolyl, benzisoxazolyl, oxindolyl, benzoxazolinyl, or isatinoyl. Also included are fused ring and spiro compounds containing, for example, the above heterocycles.
As used herein, xe2x80x9cpharmaceutically acceptable saltsxe2x80x9d refer to derivatives of the disclosed compounds wherein the parent compound is modified by making acid or base salts thereof. Examples of pharmaceutically acceptable salts include, but are not limited to, mineral or organic acid salts of basic residues such as amines; alkali or organic salts of acidic residues such as carboxylic acids; and the like. The pharmaceutically acceptable salts include the conventional non-toxic salts or the quaternary ammonium salts of the parent compound formed, for example, from non-toxic inorganic or organic acids. For example, such conventional non-toxic salts include those derived from inorganic acids such as hydrochloric, hydrobromic, sulfuric, sulfamic, phosphoric, nitric and the like; and the salts prepared from organic acids such as acetic, propionic, succinic, glycolic, stearic, lactic, malic, tartaric, citric, ascorbic, pamoic, maleic, hydroxymaleic, phenylacetic, glutamic, benzoic, salicylic, sulfanilic, 2-acetoxybenzoic, fumaric, toluenesulfonic, methanesulfonic, ethane disulfonic, oxalic, isethionic, and the like.
The pharmaceutically acceptable salts of the present invention can be synthesized from the parent compound which contains a basic or acidic moiety by conventional chemical methods. Generally, such salts can be prepared by reacting the free acid or base forms of these compounds with a stoichiometric amount of the appropriate base or acid in water or in an organic solvent, or in a mixture of the two; generally, nonaqueous media like ether, ethyl acetate, ethanol, isopropanol, or acetonitrile are preferred. Lists of suitable salts are found in Remington""s Pharmaceutical Sciences, 18th ed., Mack Publishing Company, Easton, Pa., 1990, p. 1445, the disclosure of which is hereby incorporated by reference.
The phrase xe2x80x9cpharmaceutically acceptablexe2x80x9d is employed herein to refer to those compounds, materials, compositions, and/or dosage forms which are, within the scope of sound medical judgment, suitable for use in contact with the tissues of human beings and animals without excessive toxicity, irritation, allergic response, or other problem or complication commensurate with a reasonable benefit/risk ratio.
xe2x80x9cProdrugsxe2x80x9d, as the term is used herein, are intended to include any covalently bonded carriers which release an active parent drug of the present invention in vivo when such prodrug is administered to a mammalian subject. Since prodrugs are known to enhance numerous desirable qualities of pharmaceuticals (i.e., solubility, bioavailability, manufacturing, etc.) the compounds of the present invention may be delivered in prodrug form. Thus, the present invention is intended to cover prodrugs of the presently claimed compounds, methods of delivering the same, and compositions containing the same. Prodrugs of the present invention are prepared by modifying functional groups present in the compound in such a way that the modifications are cleaved, either in routine manipulation or in vivo, to the parent compound. Prodrugs include compounds of the present invention wherein a hydroxy, amino, or sulfhydryl group is bonded to any group that, when the prodrug of the present invention is administered to a mammalian subject, it cleaves to form a free hydroxyl, free amino, or free sulfydryl group, respectively. Examples of prodrugs include, but are not limited to, acetate, formate, and benzoate derivatives of alcohol and amine functional groups in the compounds of the present invention.
xe2x80x9cSubstitutedxe2x80x9d is intended to indicate that one or more hydrogens on the atom indicated in the expression using xe2x80x9csubstitutedxe2x80x9d is replaced with a selection from the indicated group(s), provided that the indicated atom""s normal valency is not exceeded, and that the substitution results in a stable compound. When a substituent is keto (i.e., xe2x95x90O) group, then 2 hydrogens on the atom are replaced.
As used herein, the term xe2x80x9canti cancerxe2x80x9d or xe2x80x9canti-proliferativexe2x80x9d agent includes, but is not limited to, altretamine, busulfan, chlorambucil, cyclophosphamide, ifosfamide, mechlorethamine, melphalan, thiotepa, cladribine, fluorouracil, floxuridine, gemcitabine, thioguanine, pentostatin, methotrexate, 6-mercaptopurine, cytarabine, carmustine, lomustine, streptozotocin, carboplatin, cisplatin, oxaliplatin, iproplatin, tetraplatin, lobaplatin, JM216, JM335, fludarabine, aminoglutethimide, flutamide, goserelin, leuprolide, megestrol acetate, cyproterone acetate, tamoxifen, anastrozole, bicalutamide, dexamethasone, diethylstilbestrol, prednisone, bleomycin, dactinomycin, daunorubicin, doxirubicin, idarubicin, mitoxantrone, losoxantrone, mitomycin-c, plicamycin, paclitaxel, docetaxel, topotecan, irinotecan, 9-amino camptothecan, 9-nitro camptothecan, GS-211, etoposide, teniposide, vinblastine, vincristine, vinorelbine, procarbazine, asparaginase, pegaspargase, octreotide, estramustine, hydroxyurea.
The compounds of the present invention can be synthesized using the methods described below, together with synthetic methods known in the art of synthetic organic chemistry, or variations thereon as appreciated by those skilled in the art. Preferred methods include, but are not limited to, those methods described below. Each of the references cited below are hereby incorporated herein by reference. 
An approach to preparing indeno[1,2-c]pyrazol-4-ones is presented in Scheme 1 and can be used to prepare compounds of the present invention. The nitro group of dimethyl 3-nitrophthalate was reduced to the amine using catalytic hydrogenation. The aniline was acylated using acetic anhydride and pyridine as a base. A mixture of the resulting acetamide 2 and an acetophenone were treated with a strong base in an appropriate solvent at elevated temperature to give the desired triketone 3. Additional means of preparing triketones are known to one skilled in the art as described in Kilgore et al, Industrial and Engineering Chemistry 34:494-497, 1946, the contents of which are hereby incorporated herein by reference. The triketone was treated with hydrazine at elevated temperature in an appropriate solvent to give the indeno[1,2-c]pyrazol-4-one ring system. Additional means of preparing indeno[1,2-c]pyrazol-4-ones are known to one skilled in the art as described in Lemke et al., J. Heterocyclic Chem. 19:1335-1340, 1982; Mosher and Soeder, J. Heterocyclic Chem. 8:855-59, 1971; Hrnciar and Svanygova Collect. Czech. Chem. Commun. 59:2734-40, 1994 the contents of which are hereby incorporated herein by reference. The amide was deacylated by heating with a strong acid in an appropriate solvent to give aniline 4. This aniline was acylated under standard conditions using an acid chloride in an appropriate solvent to give the desired product 5.
An alternative method for making compounds of the present invention is shown in Scheme 2. The intermediate triketone 3 can be deacylated with strong acid and reacylated with an appropriate acid chloride using methods known to those skilled in the art. Subsequently, triketone 6 can the be converted to the indeno[1,2-c]pyrazol-4-one ring system using the same conditions described previously in Scheme 1.
Another method for preparing the triketones 6 of Scheme 2 employs the condensation of a 1,3-diketone 6a with 3-nitrophthalic anhydride as described in Rotberg and Oshkaya, Zh. Organ. Khim. 8:84-87, 1972; Zh. Organ. Khim. 9:2548-2550, 1973, the contents of which are hereby incorporated herein by reference. The 1,3-diketones, when not commercially available can be readily prepared by one skilled in the art by the acetylation or trifluoroacetylation of the requisite methyl ketone, R1COCH3. Reduction of the nitro derivative 6b to the aniline 6c can be accomplished in a variety of ways including catalyic hydrogenation, treatment with zinc or iron under acidic conditions, or treatment with other reducing agents such as sodium dithionite or stannous chloride. Subsequently the aniline 6c can be converted to the indeno[1,2-c]pyrazol-4-ones of this invention by acylation followed by treatment with hydrazine as described previously in Scheme 2.
Another method for making the indeno[1,2-c]pyrazol-4-one ring system is shown in Scheme 4. Dimethyl hydrazine was reacted with 3-acetylpyridine with no solvent to give the hydrazone 7. This was treated in a similar fashion as described in Scheme 1 to give the desired intermediate 8. Additional means of preparing similar intermediates are known to one skilled in the art as described in Rappoport, J. Org. Chem. 49:2948-2953, 1984, the contents of which are hereby incorporated herein by reference. This intermediate was carried through the sequence in a similar fashion as described in Scheme 1.
Another approach to preparing indeno[1,2-c]pyrazol-4-ones is presented in Scheme 5 and can be used to prepare compounds of the present invention. Treating the intermediate 5-aminoindeno[1,2-c]pyrazol-4-one with 2-(trimethylsilyl) ethoxymethylmethyl chloride (SEMCl) and a suitable base in an inert solvent under reflux gives the SEM protected intermediate. The aniline is converted to the carbamate with phenylchloroformate using methods known to those skilled in the art. This intermediate is reacted with carbaztes in DMSO at elevated temperatures and then the SEM group is removed by treating with acid in a polar protic solvent to give the desired acylsemicarbazide-containing indenopyrazole analogs.
Other features of the invention will become apparent during the following descriptions of exemplary embodiments which are given for illustration of the invention and are not intended to be limiting thereof.